Use feature(generic_associated_types) as in stable

The feature(generic_associated_types) has been recently stabilized and
does not need to be listed in the `#![feature(...)]` block.

Also, move the `where` clauses on GAT impls to after the type
assignment, taking advantage of a syntax change described here:

  rust-lang/rust#89122

apex-engine/src/lib.rs

@@ -1,3 +1,3 @@
-#![feature(generic_associated_types, type_alias_impl_trait)]
+#![feature(type_alias_impl_trait)]
 mod engine;
 pub use engine::{Engine, HEARTBEAT, REMOVE_EVENT, REMOVE_GAME};

apex-hardware/src/device.rs

@@ -121,18 +121,15 @@ impl<T: Device> AsyncDevice for T
 where
     T: 'static,
 {
-    type ClearResult<'a>
+    type ClearResult<'a> = impl Future<Output = Result<()>> + 'a
     where
-        Self: 'a,
-    = impl Future<Output = Result<()>> + 'a;
-    type DrawResult<'a>
+        Self: 'a;
+    type DrawResult<'a> = impl Future<Output = Result<()>> + 'a
     where
-        Self: 'a,
-    = impl Future<Output = Result<()>> + 'a;
-    type ShutdownResult<'a>
+        Self: 'a;
+    type ShutdownResult<'a> = impl Future<Output = Result<()>> + 'a
     where
-        Self: 'a,
-    = impl Future<Output = Result<()>> + 'a;
+        Self: 'a;
 
     #[allow(clippy::needless_lifetimes)]
     fn draw<'this>(&'this mut self, display: &'this FrameBuffer) -> Self::DrawResult<'this> {

apex-hardware/src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(generic_associated_types, type_alias_impl_trait)]
+#![feature(type_alias_impl_trait)]
 mod device;
 #[cfg(feature = "usb")]
 mod usb;

apex-mpris2/src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(generic_associated_types, type_alias_impl_trait, async_iterator)]
+#![feature(type_alias_impl_trait, async_iterator)]
 mod generated;
 mod player;
 pub use player::{Metadata, Player, MPRIS2};

apex-mpris2/src/player.rs

@@ -195,22 +195,18 @@ impl<'a> Player<'a> {
 impl<'a> AsyncPlayer for Player<'a> {
     type Metadata = Metadata;
 
-    type MetadataFuture<'b>
+    type MetadataFuture<'b> = impl Future<Output = Result<Self::Metadata>> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = Result<Self::Metadata>> + 'b;
-    type NameFuture<'b>
+        Self: 'b;
+    type NameFuture<'b> = impl Future<Output = String> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = String> + 'b;
-    type PlaybackStatusFuture<'b>
+        Self: 'b;
+    type PlaybackStatusFuture<'b> = impl Future<Output = Result<PlaybackStatus>> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = Result<PlaybackStatus>> + 'b;
-    type PositionFuture<'b>
+        Self: 'b;
+    type PositionFuture<'b> = impl Future<Output = Result<i64>> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = Result<i64>> + 'b;
+        Self: 'b;
 
     #[allow(clippy::needless_lifetimes)]
     fn metadata<'this>(&'this self) -> Self::MetadataFuture<'this> {

apex-music/src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(generic_associated_types, type_alias_impl_trait)]
+#![feature(type_alias_impl_trait)]
 mod player;
 pub use player::{
     AsyncMetadata, AsyncPlayer, Metadata, PlaybackStatus, Player, PlayerEvent, Progress,

apex-music/src/player.rs

@@ -72,22 +72,18 @@ pub trait AsyncPlayer {
 impl<T: Player + Sized> AsyncPlayer for T {
     type Metadata = <T as Player>::Metadata;
 
-    type MetadataFuture<'a>
+    type MetadataFuture<'a> = impl Future<Output = Result<Self::Metadata>> + 'a
     where
-        T: 'a,
-    = impl Future<Output = Result<Self::Metadata>> + 'a;
-    type NameFuture<'a>
+        T: 'a;
+    type NameFuture<'a> = impl Future<Output = String>
     where
-        T: 'a,
-    = impl Future<Output = String>;
-    type PlaybackStatusFuture<'a>
+        T: 'a;
+    type PlaybackStatusFuture<'a> = impl Future<Output = Result<PlaybackStatus>>
     where
-        T: 'a,
-    = impl Future<Output = Result<PlaybackStatus>>;
-    type PositionFuture<'a>
+        T: 'a;
+    type PositionFuture<'a> = impl Future<Output = Result<i64>>
     where
-        T: 'a,
-    = impl Future<Output = Result<i64>>;
+        T: 'a;
 
     #[allow(clippy::needless_lifetimes)]
     fn metadata<'this>(&'this self) -> Self::MetadataFuture<'this> {
@@ -137,18 +133,15 @@ pub trait AsyncMetadata {
 
 /// Blanket implementation for non-async Metadata sources
 impl<T: Metadata + Sized> AsyncMetadata for T {
-    type ArtistsFuture<'a>
+    type ArtistsFuture<'a> = impl Future<Output = Result<String>> + 'a
     where
-        T: 'a,
-    = impl Future<Output = Result<String>> + 'a;
-    type LengthFuture<'a>
+        T: 'a;
+    type LengthFuture<'a> = impl Future<Output = Result<i64>> + 'a
     where
-        T: 'a,
-    = impl Future<Output = Result<i64>> + 'a;
-    type TitleFuture<'a>
+        T: 'a;
+    type TitleFuture<'a> = impl Future<Output = Result<String>> + 'a
     where
-        T: 'a,
-    = impl Future<Output = Result<String>> + 'a;
+        T: 'a;
 
     #[allow(clippy::needless_lifetimes)]
     fn title<'this>(&'this self) -> Self::TitleFuture<'this> {

apex-windows/src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(generic_associated_types, type_alias_impl_trait,async_iterator)]
+#![feature(type_alias_impl_trait,async_iterator)]
 mod music;
 pub use music::Player;
 pub use music::Metadata;

apex-windows/src/music.rs

@@ -93,22 +93,18 @@ impl Player {
 impl AsyncPlayer for Player {
     type Metadata = Metadata;
 
-    type MetadataFuture<'b>
+    type MetadataFuture<'b> = impl Future<Output = Result<Self::Metadata>> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = Result<Self::Metadata>> + 'b;
-    type NameFuture<'b>
+        Self: 'b;
+    type NameFuture<'b> = impl Future<Output = String> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = String> + 'b;
-    type PlaybackStatusFuture<'b>
+        Self: 'b;
+    type PlaybackStatusFuture<'b> = impl Future<Output = Result<PlaybackStatus>> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = Result<PlaybackStatus>> + 'b;
-    type PositionFuture<'b>
+        Self: 'b;
+    type PositionFuture<'b> = impl Future<Output = Result<i64>> + 'b
     where
-        Self: 'b,
-    = impl Future<Output = Result<i64>> + 'b;
+        Self: 'b;
     #[allow(clippy::needless_lifetimes)]
     fn metadata<'this>(&'this self) -> Self::MetadataFuture<'this> {
         async {

src/main.rs

@@ -1,6 +1,5 @@
 #![allow(incomplete_features)]
 #![feature(
-    generic_associated_types,
     type_alias_impl_trait,
     try_blocks,
     const_fn_floating_point_arithmetic,

src/render/text.rs

@@ -98,7 +98,7 @@ impl StatefulScrollable {
     /// * `text`: the new text
     ///
     /// returns: Result<bool, Error>
-    ///  
+    ///
     /// # Examples
     ///
     /// ```